Peach Genetics and Breeding for the Future Ralph.scorza@ars.usda.gov
USDA-AFRS Our Goals - Develop New Fruit Varieties with: -Improved Fruit Quality and novel fruit traits - Improved Disease Resistance - Improved Growth Habit - Methods for genetic engineering of tree fruits - New, more rapid and efficient breeding methods
What have we achieved in
Stone Fruits released from AFRS NectaFest (N) (UP) July 20-Aug 5 EarliScarlet (N) July 25-Aug 10 Sentry July 20-30 Crimson Rocket (PI) Aug 15-Aug 30 Bounty Aug 20-Sept 10
Flavrburst peach Aug 20-Sept 10 SummerFest (UP) Aug 30-Sept 20 Sweet-N-UP (UP) Aug 25-Sept 10 TruGold peach August 1-10 (true from seed)
European (prune) plums Bluebyrd (black knot resistant) early Sept Orablue (extra large size) Mid Sept-early Oct HoneySweet (PPV and black knot resistant) early Sept
Pears richard.bell@ars.usdagov CLASSICAL BREEDING - HIGH QUALITY FRUIT VARIETY RELEASES: Gem Potomac Blake s Pride High Quality Fire blight resistant Sunrise Shenandoah
Improved Disease Resistance Bacterial leafspot + super-sweet fruit Past - Classical Breeding Approach: Cross resistant by susceptible Evaluate spot Choose best resistant + fruit quality
Disease Resistance Future Use molecular markers spot resistance gene - Isolate DNA from seedlings in the greenhouse. - Eliminate susceptibles based on markers. - Plant only resistant types in the field, evaluate fruit quality. (One marker probably not enough for all spot races.)
Disease Resistance Present/Future Genetic Engineering Plum pox virus Resistance Making Prunus resistant by inserting part of the PPV genome into the plant DNA (strategy similar to vaccination, use the plants natural resistance mechanism) HoneySweet is highly resistant to plum pox. Tested in field plots in Europe for 20 years with no reported natural infections. Approved for cultivation in the U.S.
Novel fruit attributes.three recommendations for the fresh industry to increase consumption: reduced inconvenience, marketing beyond just health benefits and better cooperation along the supply chain. Rabobank Report 2013
Not a bad peach. A bit messy though.. Why do I always sit in the wrong seat! Oops, now a sticky phone A candy bar would have been so much neater.
Novel fruit attributes In the late 1800s and early 1900s, Luther Burbank took on the challenge of creating a series of stoneless plums through a classic breeding approach of combining a poor quality fruit, nearly stoneless plum with commercial quality plums. While he came close he was not entirely successful
Novel fruit attributes Improving Burbank s Stoneless cultivars by identifying the gene(s) responsible for stone development 1 inch
Novel fruit attributes THE FUTURE Stoneless/seedless stone fruits nectarines, peaches, plums, cherries, apricots, almonds!!!!
Improved growth habit Past and Present - Classical Breeding: Development of peach tree growth habits more suited to highdensity production systems and mechanical thinning and harvesting. Crimson Rocket, Sweet-N-UP SummerFest NectaFest were released and new selections are in the pipeline.
Improved growth habit Extract DNA of PILLAR TREES Gene Sequencing DNA STANDARD TREES FIND THE DNA THAT IS ONLY IN THE PILLAR TREES AND NOT IN THE STANDARD TREES OR ONLY IN THE STANDARD TREES AND NOT IN PILLAR TREES
Improved growth habit We now know the genes that cause pillar, upright, weeping and dwarf peach tree growth! We can use these genes as markers for growth habit in conventional breeding and for genetic engineering to produce trees in the desired shapes. PI
Improved growth habit Changing a standard tree to a pillar tree
Improved growth habit We are now entering a stage in technology where we can foresee changing tree growth through genetic engineering by single gene engineering or by using multiple genes to create entirely new forms for specific growing systems. control pillar spreading weeping dwarf Hollender et al., Unpublished
Improved growth habit We are also investigating the development of GE dwarfing rootstocks in order to take existing popular rootstocks and add a dwarfing component. Bartlett Pear grafted to : Control rootstock GE 1 GE 2 GE 3
New breeding methods Traditional breeding of stone fruits is a 3-7 year cycle. Breeding, carried out in the field, is affected by climate, diseases, and insect pests. Not every year is successful. Pollination Protecting pollinations Field planting seedlings
New breeding methods The Future - Developing breeding systems based on genetically engineered early flowering parents, rapid cultivar development with a final product that is not genetically engineered. Plum with a rapid flowering gene produces ripe fruit 9-12 months from seed. Normally, plum fruiting requires 4-6 years from seed planting.
Conventional Breeding program with 4yr/ generation cycle T Early flowering X Conventional T 50% 50% FasTrack Breeding program T X T Two additional crosses 50% 50% T T 20 years http://ucanr.edu/sites/fastrack/ New potential varieties not GMO 8 years
Simultaneous Development of Flowers and Fruit
FasTrack plums flowering and fruiting in the field April - August Early summer Mid summer September
Early and continuous flowering and fruiting allows FasTrack Breeding to be carried out in green- or screen-house We use genetic engineering to speed the breeding process but in the final set of crosses we only select the trees that are not genetically engineered for variety development. We are working with plum breeders in California to more quickly develop improved prune varieties.
Why we need more rapid tree breeding Citrus greening Chestnut blight Plum pox virus Dutch elm disease African Fig Fly Hemlock woolly adelgid Pine Shoot Beetle Spotted Wing Drosophila Emerald ash borer Oriental fruit fly Asian longhorn beetle White pine blister rust Citrus canker Brown marmorated stink bug
Better Fruit Trees Through Research We need to hear from you with your questions, comments and hopefully your support